pH, TA issues

[anne]

Does this make ANY sense??

Day 1: fill tub. Starting values: TA 80, pH 7.3. Added 3 tbsp Baking soda.

Day 2: TA 100, pH 7.5 (I'm fine with this so far, but it starts getting weird...)

Day 7: TA 80, pH 8.0. Added 6tbsp baking soda, intending to increase TA then deal with pH later

Day 8: TA 150, pH>8.0 Added 2 oz dry acid...... 16 hrs later, TA 100, pH 7.2

Day 11: (today) TA 140, pH >8.0. Added 1 oz dry acid, now I'm waiting to see what happens.

I do not understand what keeps driving the pH up! I only add chlorine, which if anything would lower it a bit. I believe these values to be accurate- I'm using a Taylor test kit, and am careful about technique. Any ideas?

I had problems getting my pH down when I first got the tub several months ago, but it has not been an issue again till now. Back then, the tap water was STARTING at 8.0, and it was hard to decrease it. Obviously my water content is not very consistent if now I'm starting at 7.3. I have consistently hard water (500-600ppm)

One difference is that I am NOT using N2 at the moment, but I doubt that is of concern......?

[Vinny]

I do know that chlorine can affect the testing chems and maybe this is what is happening. At higher levels thay can bleach out the reactions totally.

Are you testing the tub with different chlorine concentrations? Are you using the same chlorine as before you changed out the water? The only other consideration is old testing chems (but I doubt it).

Sorry, I've had my own wierd water stuff but not this ...

You are right - N2 has nothing to do with it!

[hottub.pool_boy]

Do you hold the reagent bottles straight up and down? You should. If the bottle is held at an angle you get an inconsistent drop size. I'm sure you using the chlorine neutralizer as needed, sometimes more, sometimes less. Neighbors aren't dipping? No really, ever have the calcium fall out of solution and cloud the spa? 500-600ppm, seems like you're on the vurge of that happening. Maybe with the TA adlusted up to 140-150ppm you won't exerience the pH bounce. I think that will do it.

[In Canada eh]

Anne,

      Wish I could help but I'm in the same boat as you.  I can't figure out what is driving the ph up,  I am adding ph down at least once a week.   I use the same chems as you and also test with a T aylor kit.  

Maybe the upright bottle has something to do with it, I've never paid attention to how I add drops :-?

[anne]

Vinny- You might be on to something with the chlorine effect. Generally I'm testing the water when the chlorine is very low, but my FIRST readings (7.3 and 80) were with high chlorine. Perhaps my inital "real" pH was higher than 7.3.......That would explain the discrepancy between now and a few months ago when I was starting with 7.8-8.0, but it would NOT explain what has happened since then (pH popping up over and over).

Hot tub boy- I am very careful to hold the bottle vertically, and I have never had cloudy water due to calcium (that I'm aware of). It is crystal clear now. I have been concerned about my water hardness, but the few times I have had cloudy water, it was when I went a few days not using the tub and therefore also not treating it, and shocking has cleared it up.  

Neighbors are not dipping......at least I'm 99.9% sure of that.  

[Gomboman]

I have the same problem with a high PH. My PH out of the faucet is around 8.0. It tends to go back up even after adding dry acid. My water usually stabalizes after a month or so. I'm on a strickly dichlor diet if that matters.  

[Vinny]

anne,

Maybe this is what's going on ... You measured low so you added baking soda, it might have been a false low so you raised your alkalinity very high (PH can only go to 8.4 with baking soda) by adding more baking soda. You tested the tub, on day 7 and either the chlorine was high again OR maybe the chlorine was still high on day 2 giving you another false reading.

If your alkalinity and PH are too high it will drive your water up once you tried to adjust it (just like if your PH is too low). I think TA drops before the PH will (the buffering effect of TA).

What you may be seeing is an initial bad reading with trying to balance it ... these are wacked out now. This is my thinking.

[windsurfdog]

Also don't forget to consider the phenomenon of rising pH that occurs immediately after air and agitation is introduced to a brand new fill.  Normally my pH out of the tap is 7.3-7.4 but after introduction of air and agitation to a new fill, pH rises to 8.0 or higher...happens like clockwork for me.

[Bill_Stevenson]

I just noticed Windsurfdog's martini joke, and am giggling as I type this note.  Good one.

Anyway, Windsurfdog's point about the effects of aeration and agitation is quite right.  Other factors that affect water chemistry are also important to consider.  Our persperation is a biggie.  Another is the effect of any lotions, deoderants, perfumes, and so on.  

My observations and suggestions are made in light of the many variables that can affect our spa water.  First, don't micromanage the water.  I recommend one check per week, or if you just can't stand to leave things alone, two checks.  That is testing for TA, TDS, Free Cl, Combined Cl, Hardness, pH and so on.  Second, push the TA up to about 150 ppm before adjusting pH.  Don't go back to check TA again as it will just cause you to worry needlessly.  Third, it is not uncommon for pH to drift up for a lot of reasons (see intro remarks).  If TA is right the drift is slower, but it is not stopped.   Fourth, and this one is important, take your water sample at a time every week when the spa has been left in stasis for several hours so that the chems are thoroughly mixed and the concentrations are stable.  For example, I take my sample on Saturday morning, having last used the tub the evening before and when dichlor was last added.  I also shock at the same time every week, after my soak on Saturday night, or if something prevents that, then Sunday night.  

If you can set up a routine, and you are consistent, and you resist the urge to micro manage, the spa should prove easy to manage, a joy to use, and safe.

Take care,

Bill  

[The_Bends]

I agree completely with Bill.  Drive the TA up high. 180 or so.  Set it and forget it.

Second, eveyone should remember that pH Up (sodium carbonate) and Alkalinity Up (sodium bi-carbonate) are cousins.  Increasing your alkalinity will inherently increase your pH.  

Drive the TA up high, because you know that it will bring pH up, and for the sheer convenience of not having to adjust it again for a month.  Do this first. Then put that bottle away!

Next after the Alkalinity has risen (most chemical manufacturers say to wait 4-6 hours until testing again for good reason), THEN bring pH down with pH down.  I would take pH down to 7.2 - 7.4, especially when using chlorine.  This makes the chlorine more effective.  Again, most manufacturers recommend 4-6 hours before testing water after making changes, and I doubt that half of us on the forum actually wait (myself included).  

Finally, I know I have read here that we have figured out that sodium bicarb is Baking Soda, but I still reccomend using 'spa chemicals' in the spa.  This, at the very least, would rule the product going into the tub out of the equation, so you can focus more on what is really causing the fluctuations with your water.  

Hope it helps!

[anne]

Thanks guys. I'm trying to resist the urge to micromanage... that is why I have things checked on day 1-2, then 7-8......I was actually waiting 24 hrs before re-checking, but if my values are reliable 4-6 hrs later, that would be easier.

My habit has been to check values as I get out, before I add chlorine. Bill recommended "take your water sample at a time every week when the spa has been left in stasis for several hours so that the chems are thoroughly mixed and the concentrations are stable." Does me being in the water affect that "stasis" much? I do it then because I figure the chlorine readings are the lowest at that time. (And I conveniently finish drinking my water, swirl the cup around a few times, and fill it with tub water to test.) I am certainly NOT consistant about time of the day. I'll try to be.

I bought an awfully big box of baking soda....what is the difference between that and spa-prepared NaHCO2?

And I do NOT regualrly test hardness, TDS, or even chlorine, now that I know, for my water and usage, what amount of chlorine is needed to get to 3ppm, etc. I test hardness once in the beginning, just to see what the city is providing (always 500-600) and then I dont recheck......should I? I have only checked TDS a couple of times- when it is cloudy, or as I'm getting close to the end of 3-4 months of water, and wondering when to change it....should I already be checking it, only 12 days into a new batch of water?

[tonyp]

Out of the tap, my Ph is low and my TA is high, which makes little sense.  If I leave it alone the Ph will go to the high side, which makes sense due to the TA.  I adjust using Ph down 1-2 times a week, sometimes more often, sometimes less.  Eventually the Ph gets in range and then it's time for a water change (4 months).

[windsurfdog]

I bought an awfully big box of baking soda....what is the difference between that and spa-prepared NaHCO2?

Absolutely zero...nada...none.  Sodium bi-carbonate is sodium bi-carbonate is baking soda.  The_Bends recommended the spa specific stuff...it works too but at a greater price.  Don't be fooled by the advertised name...look at the ingredients and you'll see they are the same.

[windsurfdog]

I just noticed Windsurfdog's martini joke, and am giggling as I type this note.  Good one.

I've never been able to get past 2...especially the size I make...

[hot tub Frank]

I did not have a problem with the PH but i could not get my water hardness up.
After i put in 2 bottles of hardness up, i was still well in the lower limits. So i got some hardness up for a 60000g pool and put some of that in. That took care of my problem.